There are many head-mounted visual display devices currently in existence. The majority of these devices have been developed for use in conjunction with military applications. For example, U.S. Pat. Nos. 3,059,519; 3,205,303; 3,383,300; 3,870,405; 3,923,370; 4,040,744; 4,081,209; 4,156,292 and Re. 28,847 all disclose "heads up" display devices for military applications in which reflective devices attached to a user's helmet display imaqes which are qenerated by a small cathode ray tube (CRT) Due to the presence cf a relatively large CRT, the majority of the devices disclosed in the above-listed patents are bulky and difficult to use even in military applications where a helmet is commonly worn and user movement is often restricted. Such designs have no practical value for consumer applications where the user environment is not as restricted.
Relatively little innovation has been made in the way of consumer head-mounted video displays. U.S. Pat. No. 4,026,641 discloses a CRT qenerated head display, similar to the above mentioned patent, which suffers from the same limitations, namely impractical, bulky design. More recently, U.S. Pat. No. 4,636,866 discloses a personal liquid crystal display (LCD), device in which remotely qenerated video signals are projected via LCD screens positioned in front of the user's eyes in a helmet-visor configuration The above device uses a light-transmissive LCD screen fixed within the helmet-visor structure. The helmet is necessary in order to reduce ambient light which would make the LCD display difficult or impossible to observe, but the helmet completely restricts the user s field of vision to the imaqes projected on to the LCD screen, leaving the user effectively blind to the outside environment. This limitation is unacceptable for most business, medical, industrial and consumer applications and appears suited for only purely entertainment purposes
From the above discussion, it appears that the size and nature of the display used to present information to the user is directly related to the practicality and useful applications of a head-mounted display device. Thus far, CRT and LCD devices have proven to have limited applicability to head-mounted devices.
It is therefore an object of the present invention to provide a head-mounted display device which uses display technology which can be implemented in a compact space-efficient manner so as not to occupy a majority of the user s field of vision.
It is a further object of the present invention to provide a head-mounted display device that provides a high quality, high resolution display of visual information and is suitable for a broad range of consumer, industrial, business, medical and military application.
It is still a further object of the present invention to provide a head-mounted display device which can be easily adjusted by the user to occupy all or part of the user's field of view according to individual preference.
It is yet a further object of the present invention to provide a head-mounted display device that is easily retractable from the viewer's field of vision and which can be conveniently positioned in front of either of the viewer's eyes.
It is a further object of the present invention to provide a head-mounted display which may be used while wearing eyeglasses.
It is another object of the present invention to provide a head-mounted display device that not only displays visual information but is capable of sending and receiving audio signals.